Steam iron



E. o. MORTON STEAM IRO File 5, 1948 [6/7, I ,Go

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.9. I T TO Patented July 13, 1954 STEAM IRON Eldred 0. Morton,Mansfield, Ohio, assignor to Westinghouse Electric Corporation, EastPittsburgh, Pa., a corporation of Pennsylvania Application November 5,1948, Serial No. 58,520

2 Claims. 1

This invention relates to pressing irons of the type providing steam formoistening material being pressed and has for its object an improvediron of this type.

A further object of this invention is to provicle a steam iron of thetype generally known as the flash type, with improved steamingqualities.

Another object of this invention is to eliminate spitting of waterparticles from the soleplate during the pressing operation.

In domestic steam irons of the fi'ash type, the space available forsteam generation is Very limited; therefore, if the water does not wetthe steam-generating chamber surface, it forms globules or droplets thatfloat around over the hot surface. This phenomenon retards completeevaporation with the result that droplets of water are carried by thesteam to the soleplate of the iron, causing spotting of delicatefabrics.

To overcome this problem, I coat the steamgenerating chamber surfacewith a hydrophilic material which provides a wettable surface and causesthe incoming liquid to spread over the surface, thus providing a greaterarea of contact between the liquid and the steam generating surface.Such materials come within the class known as wetting as capillaryagents. There are several hydrophilic materials which can be used, but Iprefer to use a sodium silicate solution. Under these conditions a highrate of heat transfer is obtained, the water is quickly converted tosteam and the possibility of Water particles being entrained with thesteam and carried to the soleplate is eliminated or minimized. Althoughsodium silicate is preferable for commercial application at low cost,the steam-generating chamber may be coated with any of a number ofhydrophilic materials to condition the steaming surfaces. The followingmaterials are given by way of example: sodium carbonate, calciumcarbonate, calcium acid carbonate, magnesium carbonate, magnesium acidcarbonate, sodium bicarbonate, sodium chloride and sodium sulphate. Anyone or more of these materials may be used to condition the steamingsurfaces. These materials may be carried in solution in water or otherliquids or may merely be carried in suspension in any appropriate liquidvehicle to facilitate application to the steamgenerating surface. Theconcentrations of the above materials in the liquid vehicle is notconsidered to be important since a mixture of high concentration willrequire a smaller amount than a mixture of low concentration to providethe required coverage.

In the accompanying drawing used for illustration purposes:

Fig. 1 is a side elevation, with parts in section; and

Fig. 2 is a top plan view of the soleplate.

As shown in the above drawing, a steam iron generally indicated I0, iselectrically heated and comprises a metallic soleplate H, a sheet metalcover or shell member [2 and a plastic or wood handle I3 which arefastened together in any suitable manner. The cover houses awaterstorage chamber or reservoir I4. The soleplate may be ofconventional shape as illustrated in Fig. 2, and is provided with aheating element it which is generally U-shaped as shown by the dottedlines in Fig. 2. The heating element is preferably cast into thesoleplate, and may be of the sheathed type containing an outer tube orsheath l6 housing a coiled resistance element ll centrally disposed andspaced from the outer sheath by a highly compacted refractory insulatingmaterial l8.

A thermostat i9 is centrally positioned in the soleplate H in a well 20which is defined by a Wall 2! preferably formed integrally with thesoleplate.

The wall 2| together with an outer wall 22 and a V-shaped rib 23 definea steam-generating chamber 24 and passages 25. A plurality of outletports 26 lie in a V-shaped channel 27 adjacent to the V-shaped rib 23and are shielded from'direct communication with passages 25 by the rib.

A cover plate 28 is secured to the soleplate H by any suitable means andserves to enclose the V steam chamber 2 the passages 25 and the outletports 26, thus preventing escape of steam except through the outletports in the soleplate. This cover plate has a transverse channel 29which serves as a. connecting passage between passages 25 and theV-shaped channel 2?. The steam is thus allowed to flow from the steamchamber 2t through passages 25 to channel 29, through the channel intothe V-shaped channel 21, and from the V-shapecl channel through theoutlet ports 26 to the bottom of the soleplate.

The water reservoir Hi has a needle valve 30 by means of which itcommunicates with the steam chamber 24. This valve registers with anopening in a plate 3! which overlies an opening in the cover plate 28and is fastened thereto. The valve and plate 3! are maintained inleakproof contact by an annular gasket 32. In order to reduce theconductivity from the cover plate to the water reservoir Hi, this plateis preferably constructed of light gauge material.

3 An adjustment knob 33 serves to adjust the valve 30 in order to varythe entry of water into the steam chamber and thus controls the rate ofsteam generation.

The confining surfaces of the steam chamber 24 and the passages 25 arecoated with a hydrophilic material such as, for example, a solution ofsodium silicate, in their pre-assembly stage. The hydrophilic materialis indicated by stippling 24A. To insure that these confining surfacesare fully coated when the parts are assembled, it is expedient to coatthe upper and edge surfaces of the soleplate H. The bottom and edgesurfaces of the cover plate 28 and the bottom surface of the plate 33may also be coated, if desired. The surface of the well 20 need not becoated, since it is sealed against steam or water access. Also, thesoleplate has a heel portion 34, the upper surface of which need not becoated. Although the specific gravity of the silicate solution is notcritical and may vary over a fairly wide range, a water solution havinga specific gravity of 1.35 is preferred, since it has been foundsatisfactory for application directly to the evaporating surfaces. Theratio of NazO to SiO2 in the sodium silicate may vary over a wide rangesuch as from 1:2 to 123.75, respectively, although I prefer to usesodium silicate having a ratio of 1:322. The coated parts are then airdried and assembled into the iron.

Upon completion of the iron assembly a quantity of dilute sodiumsilicate solution, containing between per cent and per cent sodiumsilicate in water is passed into the reservoir 14 and through the valve32 while the iron is energized. This additional treatment coats thevalve stem and the orifice of valve 36 with a thin layer of sodiumsilicate which will cause the Water to flow more readily from the waterreservoir i i to the steam-generating chamber 24. To insure againstclogging of the valve a quantity of Water is then passed into thereservoir l4 and through the valve 3% in similar fashion. The iron isnow fully treated and will operate satisfactorily without the usualspitting of partially vaporized water through the soleplate. Steam ironswhich have not been subjected to the above treatment will spit water fora period of time until their steanngenercting surfaces become coatedwith lime depos left by the evaporating water. This period of 0 1c iscommonly known as the breaking in period; however, irons treated in themanner described need no breaking in period since in chest they havebeen broken in by this method of manufacture.

To operate the iron, the reservoir I4 is filled with water and the ironis energized by connecting to an electrical outlet in the usual wayprovided for electrical appliances of this type. To operate as a steamiron, the knob 33 is rotated to any steam volume position desired, thusopening the valve 39 to an extent allowing the required flow of waterfrom the reservoir to the steam-generating chamber 24. This flow is inthe nature of a dripping action, and the water drops will be caused tospread by the wetting surface and instantly flash into steam uponcontact with the hot steam chamber surface. The steam will then flowalong the channels and passages provided until it escapes through theoutlet ports 26 to the bottom of the soleplate. There its elfect is todampen the article being ressed, thus eliminating the need forpro-dampening the article as is customary when dry ironing. When it isdesired to use the iron as a dry iron in the conventional manner, theknob 33 is rotated to the closed position, thus closing the valve 32 andstopping the flow of water from the reservoir It to the steam chamber24.

While I have shown my invention in but one form, it will be obvious tothose skilled in the art that it is not so limited, but is susceptibleof various changes and modifications without departing from the spiritthereof.

What I claim is:

l. A steam iron comprising a soleplate, a vapor-generating chamber ofthe flash type, means including a valve for admitting water in drop-letform to said chamber and means for transmitting vapor from thevapor-generating chamber to the lower surface of said soleplate, saidchamberhaving side wall surfaces and a bottom wall surface, said sideand bottom Wall surfaces being coated with a hydrophilic material tocause water to spread and thereby to facilitate vaporization.

2. The structure recited in claim 1 in which said hydrophilic materialis sodium silicate.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 1,323,131 Goodfellow Nov. 25, 1919 1,571,962 Overton Feb. 9,1926 1,530,545 Swartz et a1 May 31, 1927 1,964,592 Nerad June 26, 19342,104,528 Richardson Jan. 4, 1938 2,299,789 Black Oct. 2'7, 19422,317,706 Woodman Apr. 2'7, 1943 2,336,807 Schwartz Dec. 14, 19432,387,281 Morton Oct. 23, 1945

